Various types of gas control valves have been utilized to control the flow of gas, such as gate valves, ball valves, needle valves etc. Solenoid activated control valves use a solenoid to actuate the valve mechanism. Solenoids are electromechanical devices which can produce mechanical movement in response to a magnetic field. In a typical prior art solenoid, a series of windings is wrapped around a cylindrical core to form a magnetic pole. When a voltage is applied to the windings, the magnetic field causes the armature to move relative to the pole. An oppositely directed spring returns the armature to its previous position once the applied voltage is removed.
In the aforesaid construction, the armature is driven into engagement with magnetic pole which forms a mechanical stop to limit the travel of the armature in one direction. The force at which the armature strikes the stop generates a significant sound. The level of noise produced by a conventional valve is typically not a consideration of many industrial and vehicle applications where they are employed. However, in pulse width modulated control environments where the armature is striking the stop many times per second, the noise is appreciable and very annoying, especially when employed in a consumer appliance, such as a gas stove.
Accordingly, it is an object of this invention to provide a pulse width modulated gas flow control valve which operates silently.
It is a further object of this invention to provide a pulse width modulated gas flow control valve, as aforesaid, wherein the movement of the armature is stopped magnetically in one direction and by engagement of a soft material elastomeric member with a fixed stop in the other direction.
It is a further object of this invention to provide a pulse width modulated gas flow control valve, as aforesaid, wherein the valve is durably constructed and is maintenance free.